Flight Deck Party Line/Situational Awareness: Issues as Reported to the Aviation Safety Reporting System

The Aviation Safety Reporting System (ASRS) was searched to determine errors associated with the use of the party line (PL). Pilots occasionally misinterpret and/or receive inaccurate PL information; based on this information, they make incorrect and potentially dangerous decisions. Detailed analysis revealed two types of errors: those attributed to inaccurate PL information and those resulting from incorrect flightcrew actions based on the PL. Almost half the errors involving incorrect flightcrew actions were a result of executing unauthorized clearances because of confusion caused by similar call signs. Conclusions are drawn with respect to the loss of the PL in a data link environment.